The present invention relates in general to pipe prepping or cutting apparatus, and more particularly to apparatus having anchoring or gripping means to be releasably fixed at an anchoring station against the inside or outside surface of hollow pipe to be cut or to be prepped for welding, and having tool bit carriage means driven in a rotary path by a drive motor and advanced by feed means in a precisely regulated manner relative to the anchoring station to control the metal cutting action of the tool bit means.
There are many types of tube cutters or pipe cutters known in the art. Typically these pipe cutters or tube cutters include a cutting wheel and rollers mounted on a curved frame entirely surrounding or partially surrounding the pipe and include a handle for turning the cutter devices or a mechanism for forcing the cutter wheel into engagement with the pipe and regulating the cutting force as the wheel penetrates the wall of the pipe. Cutting tubing and pipes in cramped and confined locations, as where pipe sections must be removed and new sections welded on to repair heating or fluid conduit systems, are an extremely tedious and time consuming operation when performed by such typical pipe cutters. Often numerous shifts of the pipe cutter on the tubing are required to complete the operation. In the extremely confined or close quarters encountered in many pipe and conduit installations in naval vessels, particularly submarines, the problem of rapidly and effectively cutting off pipe, or the problem of preparing the edge of pipe which has already been cut to shape it to receive a weld for rewelding (frequently referred to as "prepping"), is particularly severe.
Most of the pipe cutters or prepping devices of the type which have elongated drive screw handles for advancing the cutter wheel or prepping wheel or tools into the pipe or about the pipe and which must be rotated through a 360.degree. arc, are too large to be used effectively in such installations. Some effort has been made to alleviate these problems by providing a pipe cutting and/or preparing tool in the form of a plurality of segments which may be fitted together to form a collar encircling the pipe, and which has a rotating collar portion carrying the cutter tool which is driven by a gear mechanism around the pipe to form the cut and prepare the cut surface. However, this prior art device requires a cutter of such large size diametrically as to render it difficult to use in very confined spaces and because of the means provided for assembly and disassembly of the components, the assembly and disassembly procedure is slow and tedious, requiring approximately 25 to 30 minutes to complete the assembly of the cutting or prepping apparatus about the pipe. Also, because of the structure and the limited resistance to stripping of the members which hold the components together, the speed at which the rotary components are driven is severely limited.
Furthermore, there are many cases where the end portion of a pipe to be prepped for welding projects such a short distance from a bulkhead or wall that there is insufficient external pipe surface available on which to obtain a grip or purchase against the external pipe surface and provide an anchoring station toward which the cutting tool or the cutter or prepping device bit can be advanced along a precisely regulated feed path, and thus it is not possible in such confined spaces to achieve sufficiently precise regulation of the feed of the cutting tool or bit along the pipe axis.
Accordingly, an object of the present invention is the provision of a novel pipe cutting or prepping apparatus for cutting off pipe and/or preparing it for rewelding, which has means capable of fitting into or onto the wall of the pipe to be cut to grip the pipe wall and establish an anchoring station at locations spaced at predetermined distance from the surface to be cut or prepped, to which is coupled feed means for advancing a cutting tool and means for driving the cutting tool to achieve precisely regulated feeding of the cutting tool so as to cut or prep the pipe in a desired manner while the cutting tools are being driven.
Another object of the present invention is the provision of a novel pipe cutting or prepping assembly for cutting off pipe and/or prepping it for rewelding, wherein the pipe is located in highly confined or close quarters, which assembly has means for concurrently driving and precisely feeding along a tool advancing path a rotary cutting tool and means coupled thereto for gripping the pipe to be cut or prepped for establishing an anchoring station with respect to which the cutting tool is precisely advanced along its predetermined feed path. The apparatus includes a first type of anchor forming means for gripping the internal surface of the pipe wall of the pipe to be cut or prepped to establish the anchoring station in conditions where the exterior wall of the pipe is not sufficiently exposed, and includes a second type of anchor forming means for gripping the exterior surface of the pipe wall where the exterior surface is more conveniently accessible.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.